The Multi-Protocol Label Switching (MPLS) Label Distribution Protocol (LDP) can be used to set up Point-to-Multipoint (P2MP) and Multipoint-to-Multipoint (MP2MP) Label Switched Paths (LSPs) in a network. The set of LDP extensions for setting up P2MP or MP2MP LSPs may be referred to as multipoint LDP (mLDP), which may be specified in Internet Engineering Task Force (IETF) Request for Comments (RFC) 6388, titled “Label Distribution Protocol Extensions for Point-to-Multipoint and Multipoint-to-Multipoint Label Switched Paths”, which is hereby incorporated by reference. Certain Upstream Label Assignment (ULA) techniques may be specified in IETF RFC 6389, titled “MPLS Upstream Label Assignment for LDP”, which is hereby incorporated by reference.
Service providers continue to deploy real-time multicast applications using mLDP across MPLS networks. There is a clear need to protect these real-time applications and to provide the shortest switching times in the event of failure. The current practice for protecting services and higher applications includes the pre-computation and establishment of a backup path. Under such practices, once a failure has been detected on the primary path, traffic should be rerouted to the backup path using the control plane. However, when the node of a first P2MP LSP fails, the delay for a second external network or a client to determine the failure and switch to a second egress node for receiving the traffic may be long. Such delay may not be acceptable in some systems, e.g., for real time services such as Internet Protocol (IP) television (IPTV).